Conventionally, a device that enables viewing of stereoscopic image without special glasses, involves a display device such as a liquid crystal display (LCD) panel or a plasma display panel (PDP) having a parallax barrier, a lenticular lens, or the like (i.e., a spectral dispersion unit) disposed on a viewer-facing side thereof. Accordingly, light from left-view and right-view images displayed by the display device is separated into left and right components to produce stereoscopic images.
FIG. 14 shows the principle of an autostereoscopic image display device that uses a parallax barrier. In FIG. 14, reference numeral 1 indicates an image display panel, and reference numeral 2 indicates a parallax barrier. The image display panel 1 has vertically-aligned left-view pixels L and likewise vertically-aligned right-view pixels R, disposed in alternating columns. Also, the parallax barrier 2 has vertically-oriented slit-shaped aperture portions 2a formed in plurality thereon, and the aperture portions 2a are split by masking portions 2b extending vertically between the aperture portions 2a. With the left-eye image arranged in the left-view pixels L and the right-eye image arranged in the right-view pixels R having appropriate binocular disparity, a viewer perceives a single stereoscopic image. A viewer who wants to view the stereoscopic image with his head at a proper viewing position (viewing position 4) has left-view images 3L reach their left eye 4L via the aperture portions 2a, and has right-view images 3R reach his right eye 4R via the aperture portions 2a, such that the user perceives stereoscopic images. Here, the left eye 4L is prevented from viewing right-view image light by the masking portions 2b, and the right eye 4R is likewise prevented from viewing left-view image light by the masking portions 2b (disclosed in Non-Patent Literature 1). Also, FIG. 15 shows an example in which an image of four-view system is presented, and specifically and images A, B, C, and D are a plurality of parallax images. In FIG. 15, reference numeral 10 indicates a proper viewing position, and reference numerals A(10a), B(10b), C(10c), and D(10d) indicate positions where parallax images A(9a), B(9b), C(9c), and D(9d) are visible, respectively. In the case where a viewer has his head at the viewing position 11 for example, the viewer has the parallax image C(9c) reach his left eye 11L, and has the parallax image D(9d) reach his right eye 11R.
As shown in FIG. 15, for each of a plurality of parallax images, a position where the parallax image is visible is repeatedly arranged at predetermined intervals on a plane parallel to a panel. A viewer has parallax images visible at each two adjacent positions enter his left eye and right eye at proper positions, thereby to perceive a multi-view stereoscopic image.